Just as the last remnants of scaffolding covering the Washington Monument are coming down, workers are preparing to obscure another of the gems on the National Monument — the Dome atop the U.S. Capitol building.

The Capitol was last renovated in 1960 and is badly in need of new repairs, as weather and water damage have broken several of the ornaments along the exterior of the dome and stained many of the fixtures within the rotunda.

The restoration process, which will soon get underway, is expected to last two years — covering the exterior of the dome in scaffolding that will be lit at night and temporarily closing parts of the inner rotunda.

There are 394 steps from the ground floor of the Capitol Building to the top of the Dome. Pictured: An interior view of the Capitol Dome. At right is the sandstone wall of the original Dome, designed by Charles Bulfinch and completed in 1824.

(Sarah Mimms)

In 1855, Philadelphia architect Thomas U. Walter began work on the modern Dome, a 14.1 million pound cast-iron marvel that reaches 288 feet into the air. But after decades of wear-and-tear, the Dome is in serious need of renovations which are set to take at least two years.

(Sarah Mimms)

The Dome, which was completed in 1865, leaks. Here, above, is one of dozens of drainage mechanisms set up throughout the interior of the Dome to prevent leakage into the Capitol Rotunda.

(Sarah Mimms)

Some of the water damage is visible on these columns in the upper levels of the rotunda.

(Sarah Mimms)

(Architect of the Capitol)

To repair the internal damage, workers will put up a "donut" canopy of netting to prevent anything from falling onto the rotunda floor during construction, while allowing visitors to see the Apotheosis of Washington fresco at the peak of the Dome.

During the early and final weeks of the restoration, workers will also construct a temporary walkway for visitors, members of Congress and staff to navigate through the rotunda. During that time, none of the statues or paintings in the area will be accessible.

The "donut," pictured, was originally constructed for an earlier renovation project in 1999, when workers removed approximately 180,000 pounds of lead-based paint from the space between the inner and outer Domes.

(Sarah Mimms)

The mechanism from which the "donut" will hang is already in place at the top of the Dome, just below the Apotheosis of Washington. The canopy will be stable enough for workers to walk on, in order to retrieve fallen items as they work.

(Sarah Mimms)

Several windows in the upper reaches of the Dome are cracked. They are all, however, original to the building so rather than replacing them, workers will melt and add epoxy to fill in the cracks, much as a mechanic would repair a broken car windshield.

(Sarah Mimms)

The Architect of the Capitol's Head of Architecture, Kevin Hildebrand, demonstrates that one of the hatches — the rust-colored octagons visible from the interior of the rotunda — still opens. When the Dome was first constructed, workers would climb through the hatch to replace the light bulbs lining the interior of the rotunda. The handrail for those replacing the bulbs and outlets for those lights are still barely visible from the rotunda.

(Sarah Mimms)

Some of the "hatches" as visible from the interior of the rotunda. Notice the paint peeling on one of the octagonal pieces on the bottom left.

(Sarah Mimms)

Hildebrand points to a rusting bracket on the inside of the exterior wall of the Dome that has come almost completely free from the frame because of the sheer weight of the structure (remember, that's 14.1 million pounds of cast iron!). Visible are three nearly-square temporary support brackets that workers have installed to help bear the weight. Areas like this one will be prime targets for workers during the renovation.

(Sarah Mimms)

Even the Apotheosis of Washington at the peak of the rotunda sports a crack or two.

(Sarah Mimms)

The top of the rotunda as viewed from inside the dome. The netting above it is actually chain link fencing, designed to protect the Apotheosis of Washington below it from any falling debris. It was installed in 1960, during the last renovation effort.

(Sarah Mimms)

Another view of the interior of the Dome. No, that isn't the Death Star.

(Sarah Mimms)

The stairway leading up to the very peak of the Dome, where the lights signaling whether Congress is in session hang. Hildebrand says that AOC employees often jokingly compare the sign to a warning in The Wizard of Oz, when Dorothy and her friends enter the Haunted Forest: "I'd turn back if I was you!"

Hildebrand, however, admits that he has gone up the stairs a couple of times.

(Sarah Mimms)

The "Convene Light" at the top of the Capitol is actually four lights, which are illuminated by the Architect of the Capitol's office when either chamber of Congress is in session. The location of the light switch — which is not at the top of the Dome itself — is something of a state secret and Hildebrand would not reveal its location.

(Sarah Mimms)

Damage to the "Tholos" — the very upper reaches of the external dome upon which the Statute of Freedom sits.

(Sarah Mimms)

When standing at the top of the Capitol Dome, Pierre L'Enfant's vision for the city becomes clear. Here, a view of the Capitol Visitor's Center going down East Capitol Street to Robert F. Kennedy Memorial Stadium.